水蒸气诱导聚电解质刷的构象转变  

Switching of polyelectrolyte brushes by water vapor

作　　者：赵新军[1,2] 李祯[1] 

机构地区：[1]伊犁师范学院新疆凝聚态相变与微结构实验室,伊宁835000 [2]伊犁师范学院微纳电传感器技术与仿生器械实验室,伊宁835000

出　　处：《原子与分子物理学报》2017年第5期832-838,共7页Journal of Atomic and Molecular Physics

基　　金：新疆自然科学基金联合基金项目(2015211C298)

摘　　要：我们把Flory-Huggins模型(association models)推广应用到暴露于水蒸气中的聚电解质刷体系,考虑聚电解质-水氢键(P-W氢键)与水-水氢键(W-W氢键)、形成氢键与聚电解质链构象的耦合特性,研究水蒸气诱导的聚电解质刷构象转变的机理.研究发现,当P-W氢键效应起主导作用时,随着水蒸气浓度的增加,聚电解质刷会单调溶胀;P-W和W-W两种氢键效应,则会导致随着水蒸气浓度的增加,聚电解质刷的构象首先塌缩,然后开始溶胀的反常转变行为.基于本文的分析,可以预言,由于P-W氢键效应,聚电解质刷可以吸附水蒸气,吸附能力随聚电解质链长的增加而增强;当聚电解质链接枝密度足够高时,由于P-W和W-W两种氢键效应,增加体系中的水蒸气,会在聚电解质刷体系中形成由P-W氢键和W-W氢键交错链接的三维网络状凝胶结构.We presented a theory to study switching of polyelectrolyte brushes by water vapor. Our theory model takes account of polyelectrolyte - water （ P - W） and water - water （ W - W） molecules hydrogen bonds. We found that P - W hydrogen bonds become a key element in inducing swelling of polyelectrolyte brushes. Our results also indicate that the combination of P - W and W - W hydrogen bonds can result in a nonmonotonic dependence of a brush height on water vapor concentration： while the brush initially shrinks with increasing humidity until it reaches a minimum, and then it stretches with increasing humidity. Based on our theoretical model, we can predict that, because of P - W of hydrogen bonds, polyelectrolyte brushes can adsorb water vapor, and adsorption capacity also increases with chain -length and brush -height; P- W and W- W hydrogen bonds hybridization will lead to a hydrogen -bond network formation of 3D polyelectrolyte brushes.

关 键 词：水蒸气 聚电解质刷 氢键 构象转变 

分 类 号：O484[理学—固体物理]